Re: [PATCH v6 1/5] arm64: cpufeature: add FEAT_LSUI

[Yeoreum Yun <yeoreum.yun@arm.com>]

Hi Catalin,

> On Mon, Aug 11, 2025 at 05:36:31PM +0100, Yeoreum Yun wrote:
> > @@ -3131,6 +3132,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
> >  		.matches = has_cpuid_feature,
> >  		ARM64_CPUID_FIELDS(ID_AA64PFR2_EL1, GCIE, IMP)
> >  	},
> > +	{
> > +		.desc = "Unprivileged Load Store Instructions (LSUI)",
> > +		.capability = ARM64_HAS_LSUI,
> > +		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
> > +		.matches = has_cpuid_feature,
> > +		ARM64_CPUID_FIELDS(ID_AA64ISAR3_EL1, LSUI, IMP)
> > +	},
> >  	{},
> >  };
>
> Since this is only used in the kernel, I wonder whether we should hide
> it behind #ifdef CONFIG_AS_HAS_LSUI. Otherwise we report it as present
> and one may infer that the kernel is going to use it. Not a strong view
> and I don't think we have a precedent for this.

Agree, anyway if CONFIG_AS_HAS_LSUI, it'll be not used anywhere
right now though kernel report it has this feature.

I'll wrap it as your suggestion.

Thanks.

--
Sincerely,
Yeoreum Yun